Willie James, who rose from being the son of single mom in Harlem to a city cop and later the first black president of the union representing rank-and-file transit workers, died over the weekend. He was 73.

James led the 30,000-member Transport Workers Union from 1996 to 2000 after spending nearly 30 years as a bus driver.

Union leaders said he oversaw the advancement of minorities through the ranks even before being elected president.

And as director of the union’s training department, he guided the TWU’s first two female honchos to unprecedented promotions from cleaners to bus maintainers.

“Willie James was a pioneer in many regards,” outgoing union head Roger Toussaint said yesterday.

John Samuelson, the leading candidate running against Toussaint’s slate in the union’s elections, said James would be remembered for successfully fighting to “get us 5 percent raises in 1999, which hasn’t been matched since.”

James, who was a military veteran, became a deacon at Mount Harmon Baptist Church after retiring.